AbstractOptimum conditions of synthesis of three 4(4'-alkoxybenzoiloxy)cinnamic acids homologs were developed. Their structural characterization was carried out by the methods of element analysis and 1H nuclear magnetic resonance spectroscopy. Mesomorphic properties of the synthesized compounds were studied by polarizing thermomicroscopy and differential scanning calorimetry. Light-thermostabilizing efficiency of 4(4'-alkoxybenzoil-oxy)cinnamic acids in compositions based on polyethylene was investigated.